99 & up 7.3L Power Stroke Engine and DrivetrainDiscussion of the 99 & up 7.3L Power Stroke diesel engine and drivetrain in the 1999-Up Super Duty trucks and Excursions. No gas engine discussion allowed except on transmissions and drivetrain that pertain to all models. Please confine discussion of topics in this forum to those items that are specific to the 7.3L Power Stroke engine.
odd problem, runs poorly when fuel is low in the tank
this problem has been going on for a while, now however its gone from running poorly at 1/8 of a tank to almost 1/4 of tank.
the engine diesels loudly, and the power evaperates, a few times leaving me dead at a stop light. when it goes through one of these spells i have to put it in Neutral and put the pedal down and the whole truck shakes like im running bad gas through. ive changed the feul filter (water seperator above the engine) twice. i use diesel aditive.
its cut my tank capacity down 1/4 because there is simply no towing or highway use when its doing this.
any ideas or what i should try to find out what it is?
Re: odd problem, runs poorly when fuel is low in the tank
What year is your truck? How many miles? This sounds like classic symptoms of air leak in the fuel pickup so when the fuel level gets low it is sending aerated fuel to the pump and then to the filter where some of it goes back to the tank but some gets to the heads where it goes through your injectors. Air does not lubricate well and because it compresses more than liquid it alters the timing of your injection event. The easiest way to tell if this is the problem is to remove the hose from the hard line to the pump and replace with a short piece of clear vinyl tubing. Look at it at night with the truck idling and you will see lots of tiny air bubbles if it is not a serious leak and a steady stream if it is more severe. To fix the problem get a "pre-pump" kit from site sponsors, Diesel Innovations, Innovative Truck Products or Dieselsite. To really fix the issue consider both a pre-pump and a regulated return. Check out Hutchinaugusta's Webshots
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2002 F350 Lariat CC 4x4 Auto 4.10 DRW, DP-Tuner F5 live tuned stock, quiet, 40dd, 40, 60, 80 tow, 80e and 120r, B&W GN, BrakeSmart, 'pooned tank, tank and pre-pump mods, 2µ Dahl 100 filter, regulated return, BTS dual HPOP, AC singles with EDM 34 lpm nozzles, AIS, H2e, Spearco 6.0 IC, Hypermax 3.5" dp--> MBRP 4" 304SS exhaust, BTS tranny, 203º T-stat, Chevron ELC, coolant filter, Oilguard bypass with Schaeffer 9000, WranglerNW 200 amp alternator & Optima group 31 batteries, Nippon-Denso starter, SPA gauges, SteveRacer mods, Hella 80/100W 9007s, Hella Micro DE foglights, 1000FF driving lights, 220W backup lights, Stancor contactor, Michelin XPS Traction tires, X-Springs, Bilstein shox, custom bumpers but otherwise stock. Nov 30 '99 build engine with 16 K miles, Fluidampr, Comp Cam 910 springs, Melling LPOP and ARP headstuds.
Re: odd problem, runs poorly when fuel is low in the tank
Thanks for the post, sorry about the lack of info.
its a 99 F350 drw crew 4x4.
if this is what it is, is there no way to simply fix the leak?
asuming of course you could find it. most of what you said i have no idea how to do [img]/ubbthreads/images/graemlins/crazy.gif[/img]
if you add a pump does it replace the existing feul pump? and how difficult is this to do for the average joe?
im on vacation in montana ( from naples florida) so my money is limited and have only the most basic tools, no garage and limited skills with anything diesel.
ps. the more i think about what you said, the more im sure your right. after replacing the filters twice, and different kinds of fuel to fix the problem, it always starts near empty.
Re: odd problem, runs poorly when fuel is low in the tank
Well unfortunately, it IS a pita to drop the tank and get in there to solve the problem. It entails removing the OEM fuel pickup, replacing it with an aftermarket pickup, removing the constrictions in the OEM tubing, hanging a new filter between the tank and the OEM fuel pump. I used s.s. clamps and 3/8" i.d. fuel hose from the tank to the filter and then to the pump. A new pump is not necessary. These mods require some time and effort but are not beyond the skill of your average shadetree mechanic. Your truck will run much more efficiently and it will be much quieter. If you feel it is beyond your skills you may find a volunteer to help you from the forums. I know several active members from the Naples area. In the meantime, try not to let your tank drop below 1/2 full. A very good prepump system with a Dahl filter will cost less than you think and your injectors will thank you.
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2002 F350 Lariat CC 4x4 Auto 4.10 DRW, DP-Tuner F5 live tuned stock, quiet, 40dd, 40, 60, 80 tow, 80e and 120r, B&W GN, BrakeSmart, 'pooned tank, tank and pre-pump mods, 2µ Dahl 100 filter, regulated return, BTS dual HPOP, AC singles with EDM 34 lpm nozzles, AIS, H2e, Spearco 6.0 IC, Hypermax 3.5" dp--> MBRP 4" 304SS exhaust, BTS tranny, 203º T-stat, Chevron ELC, coolant filter, Oilguard bypass with Schaeffer 9000, WranglerNW 200 amp alternator & Optima group 31 batteries, Nippon-Denso starter, SPA gauges, SteveRacer mods, Hella 80/100W 9007s, Hella Micro DE foglights, 1000FF driving lights, 220W backup lights, Stancor contactor, Michelin XPS Traction tires, X-Springs, Bilstein shox, custom bumpers but otherwise stock. Nov 30 '99 build engine with 16 K miles, Fluidampr, Comp Cam 910 springs, Melling LPOP and ARP headstuds.
Re: odd problem, runs poorly when fuel is low in the tank
[ QUOTE ]
A new pump is not necessary. These mods require some time and effort but are not beyond the skill of your average shadetree mechanic.
[/ QUOTE ] Haulin, unless this has been going on for a while, he may have damaged his pump, But I agree that it sounds like the fuel pickup is screwed up inside the tank, keep it over half, I know that will be a crappy ride all the way back to FL. stopping for fuel every 250 miles or so, but like Haulin said, your injectors will thank you and the things mentioned above are MUCH less expensive than injector replacement.
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Jim T.*48* SLAPS Co-Founder, 30.8 yrs RETIRED UAW 6/01/06, Now an ART (Specialists Flight Chief) with the USAFR 414th MXS Seymour Johnson AFB. My pics!'03 Dually pics!, New truck, 2011 F-350 SRW LB CC. White Platinum Lariat! 4x4
Re: odd problem, runs poorly when fuel is low in the tank
[ QUOTE ]
[ QUOTE ]
A new pump is not necessary. These mods require some time and effort but are not beyond the skill of your average shadetree mechanic.
[/ QUOTE ] Haulin, unless this has been going on for a while, he may have damaged his pump,..........
[/ QUOTE ]This is true but my point was that pre-pump mods do not require dual or replacement pumps.
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2002 F350 Lariat CC 4x4 Auto 4.10 DRW, DP-Tuner F5 live tuned stock, quiet, 40dd, 40, 60, 80 tow, 80e and 120r, B&W GN, BrakeSmart, 'pooned tank, tank and pre-pump mods, 2µ Dahl 100 filter, regulated return, BTS dual HPOP, AC singles with EDM 34 lpm nozzles, AIS, H2e, Spearco 6.0 IC, Hypermax 3.5" dp--> MBRP 4" 304SS exhaust, BTS tranny, 203º T-stat, Chevron ELC, coolant filter, Oilguard bypass with Schaeffer 9000, WranglerNW 200 amp alternator & Optima group 31 batteries, Nippon-Denso starter, SPA gauges, SteveRacer mods, Hella 80/100W 9007s, Hella Micro DE foglights, 1000FF driving lights, 220W backup lights, Stancor contactor, Michelin XPS Traction tires, X-Springs, Bilstein shox, custom bumpers but otherwise stock. Nov 30 '99 build engine with 16 K miles, Fluidampr, Comp Cam 910 springs, Melling LPOP and ARP headstuds.
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